How many chickens can I house comfortably?

I am in the process (well my husband is) of building our coops and the attached run areas. Here is the set up we have.... There is a coop that is 10'X8' attached to a run that is 25'X20'. This coop is nearly finished and the run is near completion as well. The run is actually set up so that it can be divided into two separate run areas measuring 17'X20' and 8'X20' depending on if we want one large run or two separate run areas. On the other end of the runs we are building another coop that we haven't determined the size of yet but thinking it'll be about half the size of the current coop. Just based on my current setup of a 10'X8' coop and a 25'X20' run area attached how many standard size chickens can I comfortably house. We do plan to free range on occasion in the evenings after work but I dont want to take that into account in regards to the number of chickens we house.

The generally accepted space is 4 sq ft per chicken in the coop and 10 sq ft per chicken in the run. There are several factors that influence how much actual space you need, i.e., your climate. If you are in a cold climate they will spend more time in the coop in the winter and thus will require more space.

Always use the smallest number (coop vs run) when calculating your capacity. With your current coop only, I'd say 20 full size. If you add another coop that is at least 120 sq ft you could bring your total to 50 birds.